The present invention relates to a rodent control device, and, more particularly, to such a rodent control device which generates a pulsating electromagnetic field within a building. The device is controlled by a programmed microprocessor which precisely cycles a coil on and off at a predetermined duty cycle rate while cycling the device itself on and off, detects and compensates for power line cycle rates by adjusting duty cycle rates of the pulsating field, and detects circuit abnormalities and shuts down or does not energize the coil or LED indicator in the event an abnormality is detected.
A number of different electronic rodent control devices have been devised, which have been of varying degrees of effectiveness. U.S. Pat. No. 4,802,057, which is assigned to the present assignee, is an example of such a device. In the ""057 patent, a rodent control device incorporates a low voltage integrated circuit timer to generate a pulsed output at an approximate frequency of one pulse per second, with the pulses being periodically stopped for an interim period. An opto-coupler receives the timed pulses from the timer circuit and, in turn, provides an output signal to a voltage dividing circuit which gates a triac switch. The triac is thus periodically switched on at the timed rate of about one pulse per second and, in response, completes a circuit from a first power lead through a coil to a second power lead via the triac. The coil has a core associated therewith which is connected to the second power lead and which induces a pulsed, interrupted electromagnetic field onto the power line such that the entire building wiring system becomes a radiator for the pulsed and interrupted electromagnetic field.
The rodent control device described in the ""057 patent has proven to be a very successful consumer product. However, the circuit in the ""057 patent is relatively expensive since it requires the use of discrete components, including the rather expensive opto-isolator. Furthermore, it would be desirable if the device could sense abnormal coil conditions, such as coil short and open circuits, and cease operation until normal coil conditions resume. Finally, due to varying line cycle conditions, it would be preferable if the device could automatically adapt its timing cycle for differing power line cycles.
The present invention is intended to be an improvement on the circuit described in the ""057 patent.
The present invention is directed to a rodent control device which generates a pulsating, interrupted electromagnetic field via one or more coil(s) and induces it onto the power line wiring in a building via core(s) linked to the coil(s). The rodent control device uses a circuit controlled by a microprocessor which senses line voltage cycle rates and times the application of electromagnetic pulses to the power line based upon the line voltage cycle rate. The coil(s) are connected to the microprocessor to provide a coil monitoring function via which the microprocessor detects abnormalities in the coil(s) such as shorts or open circuits. Upon detection of such an abnormality, the microprocessor shuts off gate control signals to a coil switching triac and signals to an LED indicator until a normal coil condition is sensed. The microprocessor provides several precise timing cycles including a cycle for activating an LED indicator in synchronism with a time cycle for controlling the application of pulses to the coil(s). In addition, a device rest signal is generated by the microprocessor, for example, for 2 minutes out of every 6 minute period as a power saving feature.
The principal objects of the present invention include: providing an improved rodent control device; providing such a rodent control device which applies an accurately timed electromagnetic pulse to a power line to repel rodents; providing such a rodent control device which is controlled by a microprocessor; providing such a rodent control device which does not require an opto-isolator to isolate the logic circuitry from the line voltage; providing such a rodent control device which is self adapting based upon the particular cycle rate of the connected line voltage; providing such a rodent control device in which the microprocessor senses coil conditions and shuts off any gate control signals to a coil operating triac and to an LED indicator when abnormal coil conditions exist, such as short or open circuits; and providing such an rodent control device which is economical and which is particularly well adapted for its intended purpose.
Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention.
The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.